Seahorse is a Gnome front end for GnuPG, the GNU Privacy Guard program. It is a tool for secure communications and data storage. Data encryption and digital signature creation can easily be performed through a GUI and Key Management operations can easily be carried out through an intuitive interface.
GPassguard is a GTK+ frontend to the *PassGuard suite, which manages passwords in an encrypted file so that you only have to remember one. It uses the PassGuard Framework and can be interfaced with any kind of encryption via a plugin system. It allows you to copy passwords to the clipboard.
gSTM, the Gnome SSH Tunnel Manager, is a front-end for managing SSH-tunneled port redirects. It stores tunnel configurations in a simple XML format. The tunnels, with local and remote port redirections, can be created, deleted, modified, and individually started and stopped through one simple interface. It is useful for anyone wanting to securely access private services over an encrypted tunnel.
Gringotts is a small utility that allows you to jot down sensitive data (passwords, PINs, small files, etc.) in an easy-to-read, easy-to-access, and most of all very secure form. It lets the user choose from among eight strong encryption algorithms (RIJNDAEL-128, RIJNDAEL-256, SERPENT, TWOFISH, CAST-256, SAFER+, LOKI97, 3DES), two hashing algorithms (SHA1, RIPEMD 160), and two compression techniques (ZLib and BZip2) with four compression ratios. It allows the user to use any file or an entire floppy disk as a password, as an alternative to the usual text string.
Pidgin-paranoia is a plugin for Pidgin (formerly known as Gaim) that provides information-theoretically secure encrypted conversations using one-time pads. Because the plugin uses a one-time pad where the secret key has the same length as the message and the key is only used once, the encryption is information-theoretically secure. This means that from the encrypted messages the contents of the messages are not revealed. In short: If you use truly random numbers to generate the key files, and if you keep them perfectly secret, one-time pads can not be broken.
Tin Hat is a Linux distribution derived from hardened Gentoo. It aims to provide a very secure, stable, and fast desktop environment that lives purely in RAM. Tin Hat boots from CD, or optionally USB pen drive, but it is not a LiveCD in that it does not mount any file system from the boot device. Rather, Tin Hat employs a massive squashfs image which expands into tmpfs upon booting. This makes for long boot times, but remarkable speeds during human-computer interaction.